With the many problems associated with urine collection for drug testing, including difficulties involved in monitoring the collection, urine adulterants, “shy bladder” syndrome, and many others, oral fluid (saliva) emerges as a promising specimen for drug testing, because:                (1) the specimen can be collected easily, and under direct supervision, avoiding many of the collection problems associated with urine collection,        (2) because oral fluids are a filtrate of blood, the oral fluid-drug concentration should reflect blood-drug concentrations, instead of urine drug concentrations,        (3) there are very few adulterants associated with oral fluid collections, making the drug test results more reliable, and        (4) oral fluids can be used for testing by using most of the conventional screening and confirmation methods.        
However, the drugs present in oral fluids are usually not protein bound and therefore easily attach to the surface matrix of the collection devices. The technique and materials used to collect oral fluid affect the drug concentration, and different drugs may have different affinities for the collection materials. The materials for both the collection tube and the fluid absorbent used must be selected to minimize the surface bonding of the drug(s) to be detected. To date, there is no generally recognized standard for the method, the volume of specimen required, the absorbent used for collection, the material used for the collection tube, and the time interval needed to collect oral fluid specimens.
There have been a variety of methods and devices used to collect oral fluid (saliva) specimens, and some commercially available collection devices. A report prepared for the National Institute of Justice, the US Department of Justice, on “Evaluation of Saliva/Oral Fluid as Alternate Drug Screen Specimen,” authored by Dennis Crouch, et al., at http://www.ncjrs.gov/pdffiles1/nij/grants/203569.pdf, deals primarily with the use of oral fluid as an alternate drug testing specimen, and the effects of collection devices on drug concentration. Nonstimulated saliva can be collected by a simple draining (drooling) method, in which saliva is allowed to drip from the mouth into a collection container. The collection time may be up to 10 minutes in order to collect sufficient amount for testing. Saliva production can be stimulated by:                (1) simple cheek and tongue movements,        (2) chewing on a piece of inert material such as paraffin wax, rubber band, or chewing gum,        (3) sucking on a lemon drop or a small amount of citric acid.Following stimulation by one of the above methods, the oral fluid produced can be sucked up using a syringe or swabbed from the mouth. The collection time is usually 2 to 5 minutes.        
Commercially available devices usually use a combination of mechanical stimulation and collection using some absorbent materials such as cotton balls, weaved polyester pads, or sponges. The absorbent material piece is gently chewed in the mouth in order to stimulate the production of saliva and to absorb the saliva produced. After the absorbent material is saturated with the saliva, it is removed from the mouth and the saliva is extracted by squeezing through a syringe, or by centrifugation. The following are descriptions of various saliva collection devices, some of which may be historic and no longer available.
The UltraSal-2™ (Oasis Diagnostics) saliva collection device, at http://www.4saliva.com/products/ultrasal.php, is for the collection of oral fluid/saliva samples. It automatically splits the saliva specimen into two aliquots in separate collection tubes. One tube can be used for testing while the second may be used for confirmation of results or for future use. No absorbent is involved in this method. The specimen is collected by holding the mouth piece between the lips and expectorating the oral fluid through the hole in the mouth piece into the collection tubes. The process is stopped when there is sufficient specimen collected. The collection tubes are capped and the mouthpiece is discarded. The volume collected is up to the capacity of the tube; the volume recovered is 100% of the collected volume.
The Versi-Sal (Oasis Diagnostics), at http://www.4saliva.com/products/versisal.php, is a fluid collection device that incorporates a proprietary interchangeable absorbent pad. It works by placing the device pad under the tongue and collecting saliva until a novel sample sufficiency indicator is triggered, taking 1-2 minutes. The collector is then pushed down into a supplied compression tube until the pad is significantly compressed to release the absorbed saliva. The saliva specimen is forced through an outlet into a graduated tube. Recovery efficiency is about 60%.
In the Salivette® (Sarstedt) device, at http://www.sarstedt.com/pdf/katalog/en/SARSTEDT_E—0409%2042.pdf, saliva collection is carried out by chewing a cotton wool swab. Recovery of the saliva sample is achieved by returning the swab to the Salivette® tube and centrifuging the container. The volume collected is 1.7 ml; the volume recovered is 1.4 ml (82%).
In the Intercept (STC) device, a pad is swabbed in the mouth for 2 to 5 minutes, the pad is inserted into a vial and snapped off at a scoring, and the vial is capped and sealed. Others devices mentioned in the literature, including: OraSure (Epitope), Saliva Sampler (Saliva Diagnostics) and ORALscreen collector (Avitar)
There are also available several devices incorporating saliva/oral fluid collection together with drug screen testing. In some systems, the collection device is provided along with a separate drug testing strip. In others, the collection part of the system is integrated with the testing part, and the oral fluid specimen goes directly onto the testing strip. The VerOFy® (Oasis Diagnostics), at http://www.4saliva.com/products/verofy.php, incorporates rapid and standardized saliva collection with immunochromatographic test strips providing a system for delivery of immediate results in the field or at point-of-care locations. The Oraline-SalivaConfirm™ Oral Fluid Drug Test provides a simple at-home saliva collection procedure to screen for the four most popular drug classes (: mAMP, COC, OPI, THC) to determine recent usage.
Saliva QuikScreen, at http://www.spyville.com/saliva-drug-testing-kit.html, is a saliva drug test kit for opiates, marijuana, methamphetamines, and cocaine. The collection kit appears to include an absorbent pad at the tip of a syringe plunger and a syringe barrel.
It is important during the collection and handling of biological specimens to minimize specimen contamination and infection. Providing the collection apparatus in sterile packages minimizes contamination prior to use, but there still remains the potential of specimen contamination during the collection process. Moreover, sterile packaging does not reduce the potential of infection to medical personnel who handle or otherwise come into contact with the specimen vial. The present inventor is a co-inventor of a specimen collector described in U.S. Pat. No. 4,741,346 that overcomes such drawbacks. It is an apparatus for collecting biological fluids, such as sputum, that includes a specimen vial in which a funnel is inserted and which is held in a substantially upright position in a base. The base has a detachable lid that houses and holds a vial cap and which is graspable to be used to secure the cap to the vial.